The global incidence of rosacea among adults is approximately 5%, based on data from a meta-analysis and systematic review.
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The National Rosacea Society Expert Committee recently updated its phenotype-based classification system, but the global prevalence and incidence of rosacea remain unknown, wrote Lise Gether, MD, of the University of Copenhagen, Denmark, and her colleagues.
In a review published in the British Journal of Dermatology, the researchers examined the prevalence of rosacea among dermatology patients and in the general population worldwide by analyzing 32 studies including 41 populations and 26,538,319 individuals. The study populations comprised 22 from Europe, 9 from North America, 4 from Asia, 3 from South America, and 3 from Africa. Of the 32 studies, 18 included the general population and 14 included only dermatology patients.
Overall, the pooled proportion of individuals with rosacea was 5.46% in the general population and 2.39% among dermatology patients. Of note, the pooled proportions varied when the studies were grouped by diagnostic method: self-diagnosis (9.7%), physician diagnosis (5.5%), and health care database estimate (1.05%).
Rosacea prevalence by age was highest among individuals aged 45-60 years, but “based on the available data, it was not possible to make useful stratified estimates,” the researchers said.
The researchers estimated rosacea prevalence by gender using data from the 10 studies that reported numbers from both genders. Based on a population of 5,601,642 women and 3,529,559 men, the pooled proportions were similar; 5.4% for women and 3.9% for men.
“The methods used to study the prevalence of rosacea are of great importance as misclassification may be a concern,” the researchers noted. Individuals with mild to moderate rosacea might not seek medical treatment, which might contribute to the low prevalence from health care database estimates. Conversely, the high prevalence with self-reports might suggest a lack of specificity in the questionnaires.
There were no external funding sources. Dr. Gether had no relevant financial disclosures. Coauthors disclosed relationships with companies including Galderma, Pfizer, Eli Lilly, Novartis, and Janssen.
SOURCE: Gether L et al. Br J Dermatol. 2018. doi: 10.1111/bjd.16481